Add (very simple) PDF renderer.

pom.xml

@@ -25,6 +25,11 @@
 			<groupId>io.vavr</groupId>
 			<artifactId>vavr</artifactId>
 		</dependency>
+		<dependency>
+			<groupId>org.apache.pdfbox</groupId>
+			<artifactId>pdfbox</artifactId>
+			<version>2.0.20</version>
+		</dependency>
 		<dependency>
 			<groupId>org.junit.jupiter</groupId>
 			<artifactId>junit-jupiter-api</artifactId>

src/main/java/ch/fritteli/labyrinth/Main.java

@@ -7,8 +7,8 @@ import java.nio.file.Paths;
 
 public class Main {
     public static void main(@NonNull final String[] args) {
-        int width = 80;
-        int height = 40;
+        int width = 20;
+        int height = 20;
         final Labyrinth labyrinth = new Labyrinth(width, height);
         final TextRenderer textRenderer = TextRenderer.newInstance();
         final HTMLRenderer htmlRenderer = HTMLRenderer.newInstance();
@@ -18,6 +18,8 @@ public class Main {
                 .setTargetSolutionFile(userHome.resolve("labyrinth-solution.txt"));
         final HTMLFileRenderer htmlFileRenderer = HTMLFileRenderer.newInstance()
                 .setTargetFile(userHome.resolve("labyrinth.html"));
+        final PDFFileRenderer pdfFileRenderer = PDFFileRenderer.newInstance().setTargetFile(userHome.resolve("labyrinth.pdf"));
+
         // Render Labyrinth to stdout
         System.out.println(textRenderer.render(labyrinth));
         // Render Labyrinth solution to stdout
@@ -28,5 +30,7 @@ public class Main {
         System.out.println(textFileRenderer.render(labyrinth));
         // Render HTML to file
         System.out.println(htmlFileRenderer.render(labyrinth));
+        // Render PDF to file
+        System.out.println(pdfFileRenderer.render(labyrinth));
     }
 }

src/main/java/ch/fritteli/labyrinth/PDFFileRenderer.java

@@ -0,0 +1,56 @@
+package ch.fritteli.labyrinth;
+
+import lombok.NonNull;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+public class PDFFileRenderer implements Renderer<Path> {
+    @NonNull
+    private static final PDFRenderer PDF_RENDERER = PDFRenderer.newInstance();
+    private Path targetFile;
+
+    private PDFFileRenderer() {
+        try {
+            this.targetFile = Files.createTempFile("labyrinth_", ".pdf");
+        } catch (IOException e) {
+            System.err.println("Unable to set default target file.");
+            e.printStackTrace();
+        }
+    }
+
+    @NonNull
+    public static PDFFileRenderer newInstance() {
+        return new PDFFileRenderer();
+    }
+
+    public boolean isTargetFileDefinedAndWritable() {
+        return this.targetFile != null && this.targetFile.toFile().canWrite();
+    }
+
+    @NonNull
+    public PDFFileRenderer setTargetFile(@NonNull final Path targetFile) {
+        this.targetFile = targetFile;
+        return this;
+    }
+
+    @Override
+    public Path render(@NonNull final Labyrinth labyrinth) {
+        if (!this.isTargetFileDefinedAndWritable()) {
+            try {
+                Files.createFile(this.targetFile);
+            } catch (IOException e) {
+                throw new IllegalArgumentException("Cannot write to target file.", e);
+            }
+        }
+        final byte[] bytes = PDF_RENDERER.render(labyrinth);
+        try {
+            Files.write(this.targetFile, bytes);
+        } catch (IOException e) {
+            System.err.println("Failed writing to file " + this.targetFile.normalize().toString());
+            e.printStackTrace();
+        }
+        return this.targetFile;
+    }
+}

src/main/java/ch/fritteli/labyrinth/PDFRenderer.java

@@ -0,0 +1,142 @@
+package ch.fritteli.labyrinth;
+
+import lombok.NonNull;
+import org.apache.pdfbox.pdmodel.PDDocument;
+import org.apache.pdfbox.pdmodel.PDPage;
+import org.apache.pdfbox.pdmodel.PDPageContentStream;
+
+import java.awt.*;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+
+public class PDFRenderer implements Renderer<byte[]> {
+    private PDFRenderer() {
+
+    }
+
+    @NonNull
+    public static PDFRenderer newInstance() {
+        return new PDFRenderer();
+    }
+
+    @Override
+    @NonNull
+    public byte[] render(@NonNull final Labyrinth labyrinth) {
+        final PDDocument pdDocument = new PDDocument();
+        final PDPage page = new PDPage();
+        pdDocument.addPage(page);
+        try (PDPageContentStream pdPageContentStream = new PDPageContentStream(pdDocument, page)) {
+            pdPageContentStream.setLineCapStyle(BasicStroke.CAP_BUTT);
+            pdPageContentStream.setLineJoinStyle(BasicStroke.JOIN_MITER);
+            pdPageContentStream.setLineWidth(1.0f);
+            pdPageContentStream.setStrokingColor(Color.BLACK);
+            pdPageContentStream.setNonStrokingColor(Color.BLACK);
+            final float scale = 10;
+            final float margin = 5;
+            this.drawHorizonzalLines(labyrinth, pdPageContentStream, margin, scale);
+            this.drawVerticalLines(labyrinth, pdPageContentStream, margin, scale);
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        final ByteArrayOutputStream output = new ByteArrayOutputStream();
+        try {
+            pdDocument.save(output);
+            pdDocument.close();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        return output.toByteArray();
+    }
+
+    private void drawHorizonzalLines(@NonNull final Labyrinth labyrinth, @NonNull final PDPageContentStream pdPageContentStream, final float margin, final float scale) throws IOException {
+        for (int y = 0; y < labyrinth.getHeight(); y++) {
+            boolean isPainting = false;
+            for (int x = 0; x < labyrinth.getWidth(); x++) {
+                final Tile currentTile = labyrinth.getTileAt(x, y);
+                if (currentTile.hasWallAt(Direction.TOP)) {
+                    if (!isPainting) {
+                        pdPageContentStream.moveTo(x * scale + margin, y * scale + margin);
+                        isPainting = true;
+                    }
+                } else {
+                    if (isPainting) {
+                        pdPageContentStream.lineTo(x * scale + margin, y * scale + margin);
+                        pdPageContentStream.stroke();
+                        isPainting = false;
+                    }
+                }
+            }
+            if (isPainting) {
+                pdPageContentStream.lineTo(labyrinth.getWidth() * scale + margin, y * scale + margin);
+                pdPageContentStream.stroke();
+            }
+        }
+        boolean isPainting = false;
+        int y = labyrinth.getHeight();
+        for (int x = 0; x < labyrinth.getWidth(); x++) {
+            final Tile currentTile = labyrinth.getTileAt(x, y - 1);
+            if (currentTile.hasWallAt(Direction.BOTTOM)) {
+                if (!isPainting) {
+                    pdPageContentStream.moveTo(x * scale + margin, y * scale + margin);
+                    isPainting = true;
+                }
+            } else {
+                if (isPainting) {
+                    pdPageContentStream.lineTo(x * scale + margin, y * scale + margin);
+                    pdPageContentStream.stroke();
+                    isPainting = false;
+                }
+            }
+        }
+        if (isPainting) {
+            pdPageContentStream.lineTo(labyrinth.getWidth() * scale + margin, labyrinth.getHeight() * scale + margin);
+            pdPageContentStream.stroke();
+        }
+    }
+
+    private void drawVerticalLines(@NonNull final Labyrinth labyrinth, @NonNull final PDPageContentStream pdPageContentStream, final float margin, final float scale) throws IOException {
+        for (int x = 0; x < labyrinth.getWidth(); x++) {
+            boolean isPainting = false;
+            for (int y = 0; y < labyrinth.getHeight(); y++) {
+                final Tile currentTile = labyrinth.getTileAt(x, y);
+                if (currentTile.hasWallAt(Direction.LEFT)) {
+                    if (!isPainting) {
+                        pdPageContentStream.moveTo(x * scale + margin, y * scale + margin);
+                        isPainting = true;
+                    }
+                } else {
+                    if (isPainting) {
+                        pdPageContentStream.lineTo(x * scale + margin, y * scale + margin);
+                        pdPageContentStream.stroke();
+                        isPainting = false;
+                    }
+                }
+            }
+            if (isPainting) {
+                pdPageContentStream.lineTo(x * scale + margin, labyrinth.getHeight() * scale + margin);
+                pdPageContentStream.stroke();
+            }
+        }
+        boolean isPainting = false;
+        int x = labyrinth.getWidth();
+        for (int y = 0; y < labyrinth.getHeight(); y++) {
+            final Tile currentTile = labyrinth.getTileAt(x - 1, y);
+            if (currentTile.hasWallAt(Direction.RIGHT)) {
+                if (!isPainting) {
+                    pdPageContentStream.moveTo(x * scale + margin, y * scale + margin);
+                    isPainting = true;
+                }
+            } else {
+                if (isPainting) {
+                    pdPageContentStream.lineTo(x * scale + margin, y * scale + margin);
+                    pdPageContentStream.stroke();
+                    isPainting = false;
+                }
+            }
+        }
+        if (isPainting) {
+            pdPageContentStream.lineTo(labyrinth.getWidth() * scale + margin, labyrinth.getHeight() * scale + margin);
+            pdPageContentStream.stroke();
+        }
+    }
+}